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PubMed1990

Childhood cancer after prenatal exposure to diagnostic X-ray examinations in Britain.

Detailed data were provided by the Oxford Survey of Childhood Cancer OSCC on deaths from childhood cancer in Britain after irradiation of the fetus during diagnostic radiology of the mother. In each age group at death, 0-5, 6-9 and 10-15 years, excess cancer deaths decreased suddenly for births in and after 1958. A major factor was concerted action initiated in 1956 to reduce radiation exposure of fetal gonads for fear of genetic hazards. Dose reduction was achieved during 1957 and early 1958 by reducing the rising rate of obstetric radiography and by virtually abandoning pelvimetry as that had been understood. In the 1970s the rate of X-raying increased again and so did cancer risk but not significantly. Direct evidence that diagnostic X-rays can cause childhood cancer is the similar excess rate per X-ray in twins and singleton births when X-raying rate is 5-6 times higher in twins. In the past a dose-response for cancer in OSCC data based on number of films per X-ray examination was taken to be evidence for causation but dose per film varies with kind of X-ray examination. Fixed values for dose per film were mistakenly assumed by UNSCEAR (1972) and used by it and others when deriving risk co-efficients. In updated OSCC data cancer risk is independent of film number. The odds ratio for childhood cancer deaths after X-raying in birth years 1958-61 (1.23 with 95% confidence intervals CI 1.04-1.48) and the mean fetal whole body dose from obstetric radiography in 1958 (0.6 cGy) can each be derived from nationwide surveys in Britain. The corresponding risk coefficient for irradiation in the third trimester for childhood cancer deaths at ages 0-15 years = 4-5 x 10(-4) per cGy fetal whole body dose (95% CI 0.8-9.5 x 10(-4) per cGy). It is the same for cancer incidence and mortality. A lower risk in bomb survivors exposed in utero is not incompatible since its CI are wide. There is no dependable evidence that radiosensitivity is greater in early pregnancy. A significantly raised cancer rate after diagnostic X-raying supports the hypothesis that carcinogenesis by ionising radiation has no threshold.

Child↗
PubMed2002

Back pain in pregnancy--magnetic resonance imaging correlation.

AIM: To study the relationship of disk abnormality and signal changes of the uterine cervix on magnetic resonance imaging (MRI) with back pain in pregnancy at 36-39 weeks of gestation. MATERIAL AND METHODS: One hundred and five pregnant Chinese women with previous Caesarean section at 36-39 weeks gestation undergoing magnetic resonance pelvimetry performed for a study for trial of vaginal delivery were questionnaired for back pain. Sagittal T2-weighted images were analysed for intervertebral disk abnormality, and signal intensity of the uterine cervix on the same sagittal images. The findings on MRI were correlated with back pain. RESULTS: Seventy-three (70%) of the pregnant women had back pain. Disk bulge or prolapse were infrequent but correlated significantly with the presence of back pain (P=0.02). Women with back pain in the current pregnancy tended to have a higher signal intensity of the uterine cervix compared with those without (P=0.006). Women with a history of back pain also had higher cervical signal intensity compared with those without (P=0.02). CONCLUSION: Disk bulge or prolapse was associated with back pain in pregnancy but were relatively infrequent. The significant correlation of high signal intensity in the uterine cervix and back pain suggested that soft tissue laxity may be a more important cause of back pain in pregnancy than disk bulge or prolapse.

Adult↗
PubMed2003

[Functional MRI of the pelvic floor: postpartum changes of primiparous women after spontaneous vaginal delivery].

PURPOSE: Detection of morphological and functional changes of the pelvic floor with functional MRI in primiparous women after spontaneous vaginal delivery. METHODS AND MATERIALS: The study comprises 26 primiparous women after vaginal delivery and a control group of 41 healthy asymptomatic nulliparous volunteers. MRI was performed on a 1.5 T system in supine position with vagina and rectum opacified with Sonogel. The static images consisted of sagittal and axial T 2 -weighted SE sequences and functional images of true FISP sequences in midsagittal and axial planes acquired with the patient at rest, straining and during defecation. Evaluation of morphometric parameters included pelvimetry, thickness of the puborectal muscle and width of the urogenital hiatus as well as position and movement of the pelvic organs relative to the pubococcygeal reference line. RESULTS: The configuration of the bony pelvis did not differ for both groups. The puborectal muscle was significantly thinner in the study group (0.8 cm vs 0.6 cm). The functional images showed no significant differences between both groups at rest but a significantly increased incidence in the descent of the bladder neck, vaginal fornix and anorectal junction in the study group during straining. In addition, the primiparous women had more prominent rectoceles (0.6 cm vs 1.5 cm). CONCLUSION: Static imaging alone fails to demonstrate relevant pelvic floor changes and a functional method is necessary to evaluate the interactions of the pelvic organs regarding organ descent. Functional MRI of the pelvic floor is an excellent method to reveal the significant changes of the pelvic floor after vaginal birth without exposing the uterus to radiation.

Adult↗
PubMed1998

Outcome of 496 term singleton breech deliveries in a tertiary center.

The study was conducted to compare the neonatal and maternal outcome of breech infants delivered vaginally at term with those delivered by cesarean section. All singleton term breech deliveries between January 1, 1992 and December 31, 1994 were reviewed (n = 496). Criteria for eligibility for vaginal trial of labor included: frank or complete breech presentation, estimated fetal weight of 2000-3800 g, no hyperextension of the fetal head and no history of uterine scar (group A, n = 283). Patients who did not fulfill these criteria, or had an abnormal pelvimetry, were delivered by cesarean section without a trial of labor (group B, n = 213). In group A, 226 patients (80%) delivered vaginally, and 57 (20%) patients underwent a cesarean section; 70% of the nulliparae and 89% of the multiparae delivered vaginally. No differences were observed between the groups in gestational week, number of nulliparae, pregnancy complications, and rates of epidural analgesia. However, maternal age and birth weight were significantly higher in group B. No maternal or perinatal mortality occurred. The incidences of 5-min Apgar score <7, birth trauma, neonatal complications, and neonatal intensive care unit admissions were similar between the groups and in the nulliparae and multiparae of each group. Maternal morbidity was significantly lower in patients who delivered vaginally. We conclude that a trial of labor in breech presentation based on appropriate selective criteria, and an active policy of labor management performed by experienced physicians, will facilitate safe delivery in most nulliparae and multiparae.

Adult↗
PubMed1992

[Magnetic resonance tomography as the basis for biomechanical analysis. The simulation of the birth process as an example of the expanded information potentials of segmental imaging procedures].

A method is presented that enables the use of (static) informations from magnetic resonance imaging (MRI) for (dynamic) biomechanical analysis. Using a specially developed software MRI pixel matrices are colour-coded and--according to the principle of same density--line data are created. After sectional attribution of the resulting polygons a three-dimensional mesh of so-called finite elements is created which can then be used in deformation analysis. This method is exemplified by a project dealing with the simulation of birth mechanics, which is finally aimed at validating the results from radiologic pelvimetry. First analyses show that even under foetal head moulding conditions, being considered as normal, such sensitive structures as the cerebellum, brain stem as well as the ventricles with the plexus chorioidei are to be found within the maximum isobars within a range of 104-140 N(10.6-14.3 kp).

Adult↗
PubMed2000

An audit of trial of labour after previous caesarean section.

The first aim of the study was to assess the success rate of vaginal delivery after a trial of labour in women with history of caesarean delivery. The second, was to analyse the management used and suggest recommendations that might improve the outcome. The caesarean section rate in Tameside hospital, in the period of 1995 and 1996, was (11%), 20% of which were repeat caesarean sections Fifty-one per cent of those with a history of previous caesarean section were allowed a trial of labour. The success rate of vaginal delivery in cases allowed trial of labour was 70%. But, if we include the 49% of cases who had elective repeat caesarean section in the calculation, the success rate for vaginal delivery would drop to 36%. More than one previous caesarean section was the main indication for elective repeat caesarean section. The second most common indication was cephalopelvic disproportion based on X-ray pelvimetry. Other indications included pregnancy-induced hypertension, breech presentation and maternal request. The main indication for repeat emergency caesarean section was fetal distress. Other causes included failure to progress, cephalo-pelvic disproportion, tender scar, ante-partum haemorhage and one case of ruptured uterus.

Journal Article↗
PubMed2000

Undiagnosed breech in Zaria, Nigeria.

There is no certainty about the best way of dealing with a breech presentation first diagnosed in labour. In our unit, the decision to allow a trial of vaginal delivery rested on the clinical assessment of the size of the baby and the maternal pelvis, and the progress of labour. We compared the outcome of 32 cases where a breech presentation was first diagnosed in labour with 65 women where the malpresentation was diagnosed antenatally where a full assessment including ultrasound and radiological pelvimetry could be made. There was no significant difference in the mode of delivery and fetal outcome. We continue to favour careful case selection for vaginal delivery even where the breech is first diagnosed in labour.

Journal Article↗
PubMedDate not supplied

Associations between pelvic anatomy, height and year of birth of men and women in Belfast.

Standardized radiological pelvimetry was used to examine 242 male and 314 female adults attending the out-patient departments of the Royal Victoria Hospital, Belfast, Seven indices of pelvic size and shape were measured from X-rays on each individual together with social and biological factors including age, height and year of birth. The aims were to quantify any differences in pelvic anatomy between the sexes and to measure correlations between these pelvic indices and selected biosocial factors. Pelvic indices for men and women of similar stature were significantly different, with the exception of the brim index, and these anatomical changes were correlated with year of birth. The similarity of the findings in both sexes suggests common environmental factors such as nutrition are the most likely causes, rather than factors specifically associated with pregnancy and childbirth.

Adult↗
PubMed1981

Long-term effects of prenatal x-ray of human females. II. Growth and development.

Experimental studies and studies of survivors of in-utero exposure to atomic bomb blasts have shown significant stunting of growth and mental retardation following these exposures. Central nervous system damage following very low doses of x-ray at around the time of birth has also been observed in experimental animals. This long term follow-up studies of 1458 human females exposed in utero to diagnostic x-rays and of 1458 matched unexposed controls studied in Baltimore, Maryland, included measurements of height, weight and school achievement. Women who had been exposed to x-rays in utero were significantly shorter in their mid-twenties than were their matched, unexposed controls, even after adjustment for other social and economic factors. However, additional follow-up revealed that mothers of exposed women were also shorter than the control mothers. Short stature appeared to be a selective factor for x-ray during pregnancy (mostly pelvimetry, 1947-1952). Mothers' and daughters' heights were similarly correctly among exposed and control mother-daughter pairs, suggesting that the height differences between exposed daughters and their controls were due to these selective factor rather than to any direct effect of radiation on growth. Exposed women reported poorer school achievement than control women. However, except for a higher proportion of exposed women leaving school because of pregnancy, these measurements were no longer significantly different when rates were simultaneously adjusted for socioeconomic differences between exposed and control women.

Achievement↗
PubMed1991

Brachial plexus injuries in Malaysian neonates: incidence and associated risk factors.

A prospective study was carried out on 26,176 Malaysian neonates born in the Maternity Hospital, Kuala Lumpur over a 12-month period to determine the incidence and associated risk factors of brachial plexus injuries. This condition was found in 42/26,176 neonates (1.6 per 1000 livebirths). Multiple logistic regression analysis of affected and control neonates from a nested case-control study showed that increasing birth weights and breech deliveries were the significant risk factors. Our study suggests that to reduce the occurrence of this condition, there is a need for: (i) better assessment of fetal size and maternal pelvimetry to enable earlier diagnosis of cephalo-pelvic disproportion, and (ii) review of the indications and techniques of breech delivery.

Birth Injuries↗
PubMed1995

The prevention of mechanical birth trauma by means of computer aided simulation of delivery by means of nuclear magnetic resonance imaging and finite element analysis.

Anatomic disproportion gains an increasing interest in obstetrics. Imaging procedures (radiologic pelvimetry, computed or magnetic resonance imaging (MRI) fail to reflect the dynamics of delivery including deformations of the birth channel as well as of fetal structures. To validate findings of imaging procedures in this respect a method has been developed to perform a dynamic, biomechanical postprocessing of the static informations obtained from MRI. Using an especially developed software MRI pixel matrices of maternal pelvis and fetal head were color-codef1p4d--according to the principle of same density--line data were created. After sectional attribution of the resulting polygones a three-dimensional mesh of so called Finite elements (FE) was created, which then can be used for deformation analysis. Fetal head was then moved through the birth channel by means of computed simulation. This allows not only ongoing deformations to be visualized but also resulting forces to be calculated for at any time of the delivery process for any point of the anatomical model. Performing these simulations assuming various anatomic and physiologic conditions an obstetrical-biomechanical data basis could be obtained, that was implemented in a PC-based expert system. This allows interpretation of pelvimetric data with regard to birth dynamics.

Biomechanical Phenomena↗
PubMed1981

Management of term breech presentation in primigravidae.

In a prospective study of 231 breech presentations in primigravidae at term 260 (81 per cent) were delivered vaginally with no perinatal mortality. A single case of fetal injury (Erb's palsy) was recorded and only one infant had an Apgar score of under 7 at 5 minutes. In 17 patients selected for vaginal delivery, caesarean section was necessary for abnormal uterine activity, prolapse of the umbilical cord of fetal distress. Elective caesarean section wad performed if routine x-ray pelvimetry showed values below defined limits at the brim, midcavity, or outlet or if the fetal head was extended.

Apgar Score↗
PubMed1988

Magnetic resonance imaging (MRI) in obstetrics. I. Maternal anatomy.

We assessed the ability of magnetic resonance, a recently introduced imaging technique, to demonstrate the maternal anatomy in obstetrics. The signal intensity of different maternal tissues using T1 and T2 weighted sequences was examined. The bony pelvis is depicted with sufficient clarity to provide an alternative to conventional X-ray pelvimetry. The placenta and cervix have a distinctive appearance facilitating the diagnosis of placenta praevia. The unique demonstration of cervical morphology will offer the potential for investigation into the ill-understood conditions of cervical dystocia and cervical incompetence.

Cervix Uteri↗
PubMed1988

Vaginal delivery after caesarean section: is it safe in a developing country?

Many studies from developed countries have shown that a trial of vaginal delivery after a Caesarean section can be a safe alternative to repeated Caesarean section when certain criteria are fulfilled. However, few data are available from developing countries where, in most cases, there is no electronic fetal heart rate monitoring, no information about the prior section and no X-ray pelvimetry. At Gweru Hospital, 401 patients with a scarred uterus have been managed according to a standard protocol and 288 were allowed to have a trial of scar. The results show that the trial was successful in 235 mothers (82%) and there were only 2 uterine ruptures (0.7%). Postpartum morbidity was higher after Caesarean section than after vaginal delivery.

Adult↗
PubMedDate not supplied

Fast MR imaging in obstetrics.

Ultrasonography (US) is the initial imaging modality of choice for evaluation of patients in obstetrics. However, the results of US are not always sufficient. Magnetic resonance (MR) imaging, which uses no ionizing radiation, may be an ideal method for further evaluation. Although MR imaging is not recommended during the first trimester and use of contrast material is not recommended in pregnant patients, fast MR imaging is useful in various obstetric settings and can provide more specific information with excellent tissue contrast and multiplanar views. In pregnant patients with acute conditions, various diseases (eg, red degeneration of a uterine leiomyoma) may be diagnosed. MR imaging allows characterization of pelvic masses discovered during pregnancy and diagnosis of postpartum complications (eg, abscess, hematoma, ovarian vein thrombosis). In pregnant patients with hydronephrosis, MR urography can demonstrate the site of obstruction and the cause (eg, a ureteral stone). MR pelvimetry may be beneficial in cases of breech presentation. Contrast material-enhanced dynamic MR imaging allows one to evaluate the vascularity of a placental polyp, detect the viable component of a gestational trophoblastic tumor, and diagnose a uterine arteriovenous malformation. MR imaging enables diagnosis of rare forms of ectopic pregnancy and early diagnosis of ectopic pregnancy.

Adult↗
PubMed2003

Breech deliveries and cesarean section.

Breech presentation is the most common malpresentation, with about 3-4% of singleton fetuses presenting breech at delivery. Management of breech presentation has been a contentious issue with a lowering threshold for cesarean section in recent years. Perinatal mortality and morbidity are estimated to be three times that of comparable infants with vertex presentation. Breech presentation is commonly associated with certain adverse maternal and fetal factors which inherently give rise to increased perinatal morbidity and mortality. At present, most obstetricians favor cesarean delivery for uncomplicated pre-term breech. Controlled prospective studies have shown that the outcome of breech fetuses weighing more than 1500 g was not dependent on the mode of delivery. A more recent review from the Cochrane database by Grant does not justify a policy of elective cesarean section for pre-term breech. Vaginal delivery is preferred if the following criteria are met: frank breech only, estimated fetal weight of 2500-3500 g, adequate pelvimetry without hyperextended head, normal progression of labor, no evidence of fetal hypoxia under continuous fetal monitoring, and maternal weight under 90 kg. Vaginal delivery of frank breech at term may be just as safe as cesarean section when careful selection criteria are used. If these criteria are not fulfilled, or fetal monitoring cannot be performed, cesarean section is advisable.

Breech Presentation↗
PubMed1989

X-ray examinations during pregnancy: National Natality Surveys, 1963 and 1980.

Based on 1963 and 1980 National Natality Surveys, the rate of medical x-ray examinations during pregnancy per 100 mothers fell 34.2 percent. A decrease in chest x-ray examinations accounted for almost all of the decline in total x-ray examinations. The reductions were greater for older mothers and those who were not White. While the number of births fell from 4,071,000 in 1963 to 3,612,000 in 1980, the number of pelvimetry examinations actually increased by 45,000.

Adult↗
PubMed2005

Perceptions and practices of vaginal birth after Caesarean section among privately practicing obstetricians in Kenya.

OBJECTIVE: To determine perceptions, preferences and practices of vaginal birth after Caesarean. DESIGN: Cross-sectional descriptive study. SETTING: Private clinics of obstetricians in five major towns of Kenya. SUBJECTS: Obstetricians in private practice. MAIN OUTCOME MEASURES: Practice and experiences in trial of labour (TOL); need for, and application of, selection criteria in TOL; perceptions on outcomes of TOL and patient preference; perception on trends of vaginal birth after Caesarean (VBAC) and need for policy on TOL. RESULTS: Nearly all respondents (98.4%) believed in the need for, and application of, selection criteria for allowing TOL. However, only 23% believed in routine screening with radiological pelvimetry, while 63.2% believed in routine foetal weight estimation. All obstetricians (100%) have ever managed TOL in private practice, and 74% had managed at least one case in the last six months. Despite lack of tangible selection criteria, 83.1% think that most women prefer TOL while 95.1% discourage it if perceived as inappropriate. Failure rate of TOL was perceived to be more than 50% by 35.2% of the respondents. A majority of the respondents (about 75%) would prefer TOL on themselves or their spouses. Those who perceived that there was a falling trend of VBAC were 58%, citing increased demand by mothers (45.7%), obstetricians' convenience (40.0%) and fear of litigation (26.8%) as the reasons for this observation. A fluid policy of "TOL whenever it is deemed as appropriate" was preferred by 88.7%. CONCLUSION: The perception of obstetricians is that desire for VBAC predominates over elective repeat Caesarean. However, consensus on appropriate selection criteria is lacking, which leaves the obstetrician in a management dilemma. Hence, there is need to study outcomes of both ERC and TOL in order to come out with objective policy guidelines on management of one previous Caesarean in pregnancy.

Adult↗